Every setting on the Print, Filament and Printer tab has either a locked or unlocked icon next to it. The locked lock icon indicates that the value is the same as in the currently selected profile. As soon as the value is changed, the icon changes to ublocked lock and back arrow appears, which lets you reset back to the value from the print profile. In addition to that, the label turns blue. This enables you to quickly spot settings that has been changed.
If you have one of the several different types of color blindness, you can customize some of the colors QIDISlicer uses. Click on the red question mark in the Print, Filament or Printer settings tab. Then you can click on one of the two colors at the bottom of the new window and set a different color.